Digital

[krishtriram]

Dear All,

Can someone clearly explain the difference between a latch and a Flip flop

and where can i find information in the web about Counters,Shift Registers and Flip flops with their Timing diagrams & clear explanations.

 

[miro]

flip flops can be considered as a 1 bit memory that changes its output according to the inputs and the clock....like S-R flip flops, D flip flops..
latches can be made of flip flops also...the meaning of a latch that when there is a certain input there is a certain output wich doen't change any more if the input is changed...this is the meaning of latching

 

[laroche73]

FF vs. latch

Both flip-flops and latches are digital storage elements.

A latch will follow it's input as long as the latch enable pin is active. When LE goes inactive, the latch retains or "latches" the last state of the input. Flip-flops (aka bi-stable multivibrators) only change state when the input clock changes, there is no "follow" mode.

Miro's right to point out there are different types of flip-flops; RS, JK, D, T, also clocked and non-clocked versions. The type D (or data) flip-flops are the most common and are usually positive-edge triggered, JKs are the most flexible and are usually negative edge triggered (in 74xx or CMOS logic).

The flip-flop is often a more useful building block in digital circuits. If you can find an old copy of the "TTL Cookbook" from Don Lancaster, it has a good section describing the different types and operation of various storage elements.

- CAL